| Abstract: | Citrus fruits were treated with wax coatings containing sodium 2-phenylphenate tetrahydrate (SOPP) and stored at 10 °C. No injuries appeared during 30 days' storage in Valencia oranges sprayed with waxes containing up to 4.75% of SOPP, or during 70 days' storage in Shamouti oranges and in grapefruit dipped in waxes containing up to 2.16% of SOPP. In Shamouti oranges and grapefruit dipped in waxes containing 3.1 to 3.88% of SOPP, injuries appeared at the beginning of storage. In non-injured fruits, the amounts of SOPP applied by waxing did not exceed 74.7 μg/cm2 of the fruit surface and the 2-phenylphenol (OPP) residues in the fruits did not exceed 36.8 parts/million; in injured fruits the amounts of SOPP applied varied between 105.1 and 211.3 μg/cm2 and the OPP residues between 41.5 and 123.6 parts/million. In non-injured fruit the amount of wax applied did not exceed 3.46 μl/cm2; in injured fruits the figure varied between 3.19 and 6.2 μg/cm2, suggesting that the wax coating concentrates at some places on the peel, causing injuries to the fruit. In injured grapefruit 7.93 μl/cm2 of wax was found on the injured part of the peel, and 3.21 μl/cm2 on the non-injured part, so that 124.6 μg of SOPP/cm2 corresponding to 61.6 parts/million of OPP in the fruit was applied to the fruit without causing injuries. |
